Pedal stroke analysis with Powertap advanced metrics

[ed72]

In any case to support what took me almost a year to figure out and what I wrote, here is a study showing the delay in oxygenation in the supine recumbent position vs upright. Basically, approach threshold power slowly and be extremely warmed up or primed for a hard effort compared to on an upright. Otherwise, you will feel "lactic acid" in your legs prematurely (and lower critical power...NB). I believe increase cadence also helps the hemodynamics but I don't have such a study to support for the supine position.

WRT scraping and pulling. Can you please show any study to support any benefit? Bent or upright? They all actually support the opposite. This is not an N = 1, ED72 observation. I wasted 9 months following that hogwash.

On uprights I'll even go further out on a limb, pulling back is the primary cause of lower backpain on long rides.

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/EP086304

 

[Balor]

Bent or upright? They all actually support the opposite.

There are actual bent studies that examined THAT? I'd like to have a look as well!
Anyway, you seem to agree with most stuff Railgun creators say, Kent Polk is surely a powerful rider... and heavily advocates "scraping". Learn from the fast guys, huh?

Until there are actual studies, we should keep an open mind... not as open that our brains fall out to be sure. I'd really like to see Kent Polk's metrics.

 

[RojoRacing]

Too many people in cycling testing things expecting a certain result over those who are capable of being completely unbiased and immune to placebo.

 

[AlexisBV]

Wow guys, thanks for all the feedback - I'll admit that at points it got a bit too medical for my understanding, but I feel less guilty now for my imperfect circles

My goal is naturally to reduce wasted effort, so I don't burn myself out unnecessarily. I understand that not all muscles will be able to really contribute, but if I'm able to either recruit unused resources to help apply torque, or at least prevent them from being counter-productive, I think it's worth looking into.

That being said, I'm having a look at possibly swapping cranks but for the moment I'm not sure how much trouble that's going to be (and how much "vacation" money would go into that). I'm still using the stock 170mm cranks that go with the MegaExo BB from the S30. I don't have the newer chainstay that allows different BB types to be used. I think I've seen some compatible cranksets down to 165mm but I don't think there's much available that's shorter than that. I don't have the tools to shorten an existing crank myself.

For today's workout I've stretched the boom by 5mm, and over the 90 minutes of pedaling I didn't really feel much of a difference, but the pedal metrics seemed to show a marginal reduction in the "pushing-in-the-wrong-direction" during the upstroke. I'll see if I can play around with the Qring settings before my free trial with Rouvy expires (where I can see the metrics).

 

[paco1961]

Wow guys, thanks for all the feedback - I'll admit that at points it got a bit too medical for my understanding, but I feel less guilty now for my imperfect circles

My goal is naturally to reduce wasted effort, so I don't burn myself out unnecessarily. I understand that not all muscles will be able to really contribute, but if I'm able to either recruit unused resources to help apply torque, or at least prevent them from being counter-productive, I think it's worth looking into.

That being said, I'm having a look at possibly swapping cranks but for the moment I'm not sure how much trouble that's going to be (and how much "vacation" money would go into that). I'm still using the stock 170mm cranks that go with the MegaExo BB from the S30. I don't have the newer chainstay that allows different BB types to be used. I think I've seen some compatible cranksets down to 165mm but I don't think there's much available that's shorter than that. I don't have the tools to shorten an existing crank myself.

For today's workout I've stretched the boom by 5mm, and over the 90 minutes of pedaling I didn't really feel much of a difference, but the pedal metrics seemed to show a marginal reduction in the "pushing-in-the-wrong-direction" during the upstroke. I'll see if I can play around with the Qring settings before my free trial with Rouvy expires (where I can see the metrics).

http://www.bikesmithdesign.com/Short_Cranks/

see above link for great info/supply on short cranks. He's a tremendously knowledgeable fabricator and happy to correspond via email. I got my 160 (46/36) from him and love the setup.

I was originally running the 172.5 cranks I pirated out of one of my DFs when i first built up the S40 but was having knee issues most likely do to too acute a knee angle on the top of the stroke. The knee problems disappeared as soon as I switched to the 160. It's not a big project. Many youtube videos out there that are great if you have a little mechanical ability. If you're not comfy with the work it is an easy swap out at your LBC.

 

[Balor]

Too many people in cycling testing things expecting a certain result over those who are capable of being completely unbiased and immune to placebo.

Come to think about it, a person who is completely unbiased and immune to placebo would qualify as clinically depressed at the very least. A certain level of positive self-delusion is not only normal, but highly adaptive as it seems.

 

[bladderhead]

I agree with paco1961. Short cranks, and lengthen the boom. Easy to do. And it improves the steering.

On a lighter note, I agree with Balor. Sick, sick universe. The only sane response is to go mad. So I am the owner of two recumbent bicycles. But for some reason cycling does cheer me up, despite the breathlessness.

 

[chicorider]

Cobb Cycles makes shorter cranks for SRAM bottom brackets. I have their 160mm set on my V20. A bit pricey for what they are, but they work well. Crupi also makes shorter cranks for Shimano bottom brackets. Less expensive, but partly because they don't come with chainrings (which I actually prefer). I have their 160mm Rhythm set on my S40, and they work well too. Crupi is a BMX brand, but these cranks fit double rings perfectly. They also go all the way down to 130mm.